The present invention is directed to electronic packaging and, more particularly, is directed to an apparatus and method for removing a bonded lid from a substrate. Electronic packages typically utilize a multilayer ceramic substrate. Semiconductor chips and devices are attached to conductive metal pads on the substrate. These pads are connected to conductive wiring channels which are distributed throughout the layers comprising the substrate. The wiring connects the semiconductor chips and devices on the top surface of the substrate with metal pads on the bottom surface of the substrate which supply the I/O (input/output) connection to the system board. Electronic packages are often sealed with lids which are bonded to the substrate using adhesives. The lids provide a variety of purposes. They can provide a sealed environment for the semiconductor devices attached to the substrate, prevent physical damage to the semiconductor devices from handling and transportation, and may be a necessary component to the thermal characteristics of the electronic package. Although the lid attach process has high yield, high volume products still have a yield loss due to lid attach or seal defects which cannot be reworked easily. The high strength of the adhesive makes it difficult to separate lids from substrates once they are bonded together. Often there are no physical features on the lid which would allow one to grip it for separation. Another problem is avoiding damage to the substrate or the semiconductor devices attached to the substrate during separation of the lid from the substrate.
There are a number of solutions proposed by others for separating adhesively bonded components. Carmichael et al. U.S. Pat. No. 5,505,433, the disclosure of which is incorporated by reference herein, discloses an apparatus and method for removing a sheet of material anchored to the floor. The invention requires surface area and features not available in an electronic packaging application, and creates a high concentration of stress which would expose the substrate to damage from excessive bending moments.
Busch, U.S. Pat. No. 5,335,892, the disclosure of which is incorporated by reference herein, discloses a removable adhesively mounted retention plate and Ostendorf et al. U.S. Pat. No. 5,837,556, the disclosure of which is incorporated by reference herein, discloses a method of removing a component bonded to a substrate utilizing a push pin to contact the component and force the component away from the substrate. These inventions create high concentrations of stress which would expose the substrate to damage from excessive bending moments.
Jacobs, U.S. Pat. No. 5,375,319, the disclosure of which is incorporated by reference herein, discloses a removal tool for removing a component bonded to a printed wiring board. A torque handle assembly is coupled to a jaw assembly that is rotatable to apply torque to the component to break the bond between the component and the printed wiring board. Minahan, U.S. Pat. No. 5,432,318, the disclosure of which is incorporated by reference herein, discloses an apparatus that uses shear force for segmenting a stack of bonded IC chips into shorter stacks. Both inventions could expose semiconductor devices attached to a substrate to damage from the lateral or rotational movement of the lid.
Zabel et al. U.S. Pat. No. 5,868,297, the disclosure of which is incorporated by reference herein, discloses a device for separating components from a substrate using leverage and heat. The invention does not offer a method to grasp the lid and uses straight tensile force which would result in excessive force to the substrate. Also, the application of heat is undesirable in an electronic packaging application.
Notwithstanding the prior art solutions to the problem, there remains a need for an apparatus and method to separate a bonded lid from substrates of variable size without damaging the substrate or semiconductor devices attached to the substrate.
Accordingly, it is a purpose of the present invention to have an apparatus and method to separate a bonded lid from substrates of variable size without damaging the substrate or semiconductor devices attached to the substrate.
It is another purpose of the present invention to have an apparatus and method to separate a bonded lid from a substrate in which heat is not used.
The present inventors have proposed an apparatus and a method which fulfills the purposes of the present invention by utilizing a set of variable size, high pressure jaws that have the capability of grasping vertical surfaces of the lid firmly and variable size nesting jaws which provide support of the substrate. A mechanical advantage is provided to place the adhesive seal in tension and create a peeling action which separates the lid from the substrate with minimum force and without damage to the substrate or attached semiconductor devices.
These and other purposes of the present invention will become more apparent after referring to the following description considered in conjunction with the accompanying drawings.
The purposes and advantages of the present invention have been achieved by providing, according to a first aspect of the invention an apparatus for separating a bonded lid from a substrate, comprising;
a first set of jaws for holding the substrate;
a second set of jaws for gripping a lid bonded to the substrate; and
means for pivoting said second set of jaws with respect to said first set of jaws so as to separate the lid from the substrate.
According to a second aspect of the invention, there is provided an apparatus for separating a bonded lid from a substrate, comprising;
a first set of jaws for holding the substrate;
means for gripping the lid;
means for pivoting the means for gripping the lid.
According to a third aspect of the invention, there is provided a method of separating a bonded lid from a substrate comprising the steps of:
providing an apparatus comprising a first set of jaws for holding the substrate and a
set of jaws for gripping a lid bonded to the substrate;
placing the substrate with the bonded lid in said apparatus; and
pivoting said second set of jaws with respect to said first set of jaws so as to separate the lid from the substrate.